1. Field of the Invention
The present invention relates to edible oil/fat compositions (the in this description term "oil/fat composition(s)" shall mean composition(s) containing oil and/or fat, as principal component, and other desired components, and more particularly to edible oil/fat compositions comprising a diglyceride-containing glyceride mixture and a phospholipid having a specified composition, and thus having the advantages of good stability against oxidation and heat which may occur during cooking, for example, deep- and pan-frying, roasting, and baking, and of providing little greasy or oily distastefulness and no heavy feeling in the stomach when taken in a raw state, as such when contained in salad dressing, mayonnaise, or the like.
2. Description of the Prior Art
In these days there are used various edible oils most of which include soybean oil, rapeseed oil, corn oil, cotton seed oil, safflower oil, sunflower oil, and sesame oil either alone, respectively, or in combination, in the form of a mixture or composition. More recently, there is a tendency for consumers to like light or soft taste and flavor (referred to as taste/flavor hereinafter) rather than heavy or rich foods. Because it is difficult to mix with digestive juice compared with other essential nutrients, such as, proteins and carbohydrates, the fats and oils tend to stay for a longer time in the digestive tract, and this is considered a cause of physiological discomforts, such as, a heavy feeling in the stomach caused by taking largeamount greasy or oily food, but they are very important for making the taste and appearance better. An actual problem with oils and fats therefore resides in the incompatibility between their effect which may cause physiological discomforts, such as greasy distastefulness and a heavy, feeling in the stomach, and their effect of improving the taste/flavor and appearance.
In addition, edible oils and fats plays important role for cooking from the aspect of function, for example, in order to prevent food material from burning and sticking to cooking utensils, baking molds, top plates, for instance, during the baking cakes or breads, or frying in a pan.
On the other hand, there are a number of surface active agents used as mold-releasing agents for use in cooking, for example, baking sponge cakes or frying eggs, so as to prevent dough or eggs from burning and sticking and above all, lecithins are known as specifically effective for this purpose. Thus vegetable oils containing lecithin(s) added thereto are used as mold releasing oils. Lecithins also have a anti-spattering effect for cooking, and for this reason, lecithin-added oils are available on the market as "reduced-spattering oil for roasting on iron plate".
The term "lecithins" refers herein to phospholipid mixtures containing, as major gradients, phosphatidyl choline, phosphatidyl ethanolamine, and so on. Typical lecithins are obtained from soybean or egg yolk by extraction and purification.
Natural lecithins including lecithins from soybean and egg yolk are labile and, even if protected by oil or fat, turn black brown (browning phenomenon) as the result of heating. The decomposition and denaturation products emit a bad smell and an offensive odor, resulting in an impairment in the taste/flavor of food. For this reason, the uses and amounts of lecithins are limited at present. For the purpose of overcoming the difficulty with respect to lecithins, some approaches have been made, for example modification, such as hydroxylation, of lecithins (U.S. Pat. No. 3,661,605), and the use of specified HLB lecithins (U.S. Pat. No. 3,896,975). Japanese patent publication B 61-48520, Japanese patent publication A 54-126 206 and Japanese patent publication A 54-127 408 disclose the use of mixtures of lecithin with salts of organic acids and amino acids. The problem is not substantially solved.